SU1280045A1 - Method of processing used solution for pickling copper - Google Patents

Abstract

The invention relates to a method for treating a spent solution (RR) for copper etching and can be used in the regeneration of solutions in radio electronics. The purpose of the invention is to increase the working capacity of the solution. Sodium sulphide is introduced into the PR until the content of copper ions in the solution (P) in the range of 90-120 g / l P for copper etching, containing hydrochloric acid, hydrogen peroxide and copper chloride, is monitored during the etching process for copper content. When the content of copper ions in P is greater than 120 g / l, the OR is drained and treated with sodium sulfide. Copper sulfide is precipitated, the precipitate is filtered off, and P is adjusted with hydrochloric acid to a concentration of 100 g / l and returned to the process cycle again. Then the process of obtaining the content of C ions 180 g / l P is regenerated again by the method described above. This is repeated up to three times (L times. After that, the rate of pickling abruptly feeds, and P is drained. The pickling rate of P after regeneration is somewhat higher than before processing, table 1 to 00 4)

Description

.

The invention relates to the chemical treatment of metals, in particular, to the technology of multiple use of the solution for etching copper, can be used in the manufacture of electronic equipment.

The purpose of the invention is to increase the working capacity of the solution,

 The proposed method for regenerating the copper etching solution involves adjusting the solution with hydrochloric acid after reaching a certain amount of copper ions.

When bivalent copper is accumulated in a solution of more than 120 g / l, the waste solution is discharged into a separate container and processed with a calculated amount of sodium sulfide. The amount of sodium sulfide is calculated by the formula. Then the solution is filtered, adjusted by hydrochloric acid according to chemical analysis to its content in a solution of 100 g / l, settled and returned to the technological cycle.

We again carry out the etching after the first regeneration until the content of copper ions in the solution is 180 g / l. The waste solution is again discharged into a container and treated with a calculated amount of sodium sulfide. The solution is filtered and adjusted with hydrochloric acid in a manner similar to the first regeneration. After the second regeneration, etching is again carried out until the content of copper ions is 180 g / l. The operations of copper deposition in the form of sulfide, filtration and adjustment of the solution with hydrochloric acid are carried out similarly to the first and second regeneration plants.

After the third chemical regeneration, the solution is returned to the process cycle and etched until a sharp decrease in the etching rate.

The study was carried out with peroxide-copper-chloride pickling solution. Sodium sulfide crystalline hydrate is used as a reagent.

The composition of the etching solution for regenerated media contains g / l:

Chlorine copper

(in terms of

on metal) 180

Sol Na Acid

| (35% concentration), HC1 100

.-

0

Hydrogen peroxide, H Oj33 Sodium chloride 100 During the etching process, the copper content in the solution is periodically monitored, samples are taken and analyzed by an analytical method. For the experiment, spent pickle is used with a total copper content, for example, 180 g / l. Under normal conditions, copper is precipitated until a copper concentration of 120 g / l is reached. The copper sulfide precipitate is separated by filtration. Then, the filtrate is corrected with hydrochloric acid, based on chemical analysis data, and defended within 24 hours. The copper-specific solution is returned to the process cycle and copper is poisoned in it. This solution has an improved etching quality and the etching rate in it increases. The subsequent deposition of copper is carried out similarly to the previous one. When the concentration of copper in the solution is close to the optimal 90-120 g / l, the etching rate is greatest in the range of 0.0376-0.0575 g. Moreover, the etching rate in the updated copper deposition solution is greater than in the spent concentration within the optimum concentration. After three times precipitation, the etching rate drops sharply.

To precipitate the required amount of copper, a preliminary calculation is carried out, based on the reaction equation: CuCl Na2S CuS4- + 2 NaCE. The calculation of the required amount of sodium sulfide, taking into account the water of crystallization required to precipitate 60 g / l of copper in our example:

, G MgK1 .-.

240

M,

50

55

where m | 78 molecular weight NajS; M, 135 molecular weight CuCE;

 2

K - the amount of chlorine copper Cu 2,

., M

where Cuj, g / l is the amount of copper ions required to precipitate

64 - atomic mass of copper 240 - molecular weight of crystalline hydrate 9 HjO.

In our example, C is 60 g / l, therefore

- Na, S-9H O 225 g / l

 2 hr

In the process of precipitation and copper sulfide, sodium sulfide partially interacts with hydrochloric acid; therefore, it is necessary to take sodium sulfide by 1.2-1.3 times more compared with stoheometry.

The etching rate in both the spent and regenerated solution is determined by changing the weight of the copper sample for 10 min at 40 ° C and vigorous stirring. Sample weight is 1 g. The accumulation of sodium chloride up to 100-110 g / l and sulphate of ions up to 25 g / l does not affect the etching rate of copper.

The results of the experiments carried out after three times precipitation of the spent pickling solution are given in the table.

To justify the limits, we present the results of experiments. The first addition of sodium sulfide reagent is introduced at a copper concentration in the solution of 120 g / l, and the amount of the reagent is added, based on the calculation, maintaining the copper content in the solution from 90 to 120 g / l.

Using sodium sulfide, it can regenerate the waste solution three times. The etching rate after the third regeneration is laid in the speed fork. Moreover, the etching rate in the solution after regeneration with a copper content of 90-120 g / l corresponds to 0.0376-0.0575 g, while the etching rate in the developed solution with a copper content of 90-120 g / l is 0.0278 -0.0353 g. Thus, after chemical regeneration, an increase in the etching rate is achieved.

In a known method, a solution for etching copper, containing hydrochloric acid, hydrogen peroxide and chlorine copper, is adjusted by means of metered delivery of hydrochloric acid and hydrogen peroxide in the accumulation of ions of one

O

50

0

5 0 5

0

novalent copper is more than 1-1.5 g / l, since the accumulation of monovalent copper more than 1.5 g / l sharply decreases the etching rate. The disadvantage of this method is that with the accumulation of divalent copper Cu up to 180 g / l 5/6 of the spent solution is discharged into wastewater.

In comparison with the known method of the present invention, an increase in the etching rate in the regenerated solution is achieved.

In the known method, after the treatment of the solution, the efficiency of the etching process is reduced due to the impurities formed, and in the proposed method the impurities do not affect the etching process, since the low solubility of copper sulfide, therefore contaminations that are almost unavoidable during etching, in our case, affect less than when using the effect of changing the solubility of copper sulfate. In addition, when treated with sodium sulfide, impurities in the solution, tin, lead, and other metals are precipitated along with copper, which, further purifying the solution, increases the utilization rate of the solution up to three times.

The implementation of the proposed method of regeneration of the spent pickling solution allows the solution to be returned three times and, moreover, in the regenerated solution, the etching takes place at a faster rate than in the solution before processing.

Claims (1)

The invention relates to the chemical treatment of metals, in particular, to the technology of repeated use of the solution for etching copper, can be used in the manufacture of electronic equipment. The purpose of the invention is to increase the working capacity of the solution. The proposed method for regenerating the copper etching solution involves correcting the solution with hydrochloric acid after reaching a certain amount of copper ions. When bivalent copper is accumulated in a solution of more than 120 g / l, the waste solution is discharged into a separate container and processed with a calculated amount of sodium sulfide. Co. the amount of sodium sulfide by formula. Then the solution is filtered, adjusted by hydrochloric acid according to chemical analysis to its content in a solution of 100 g / l, settled and returned to the production cycle. We again carry out the etching after the first regeneration until the content of copper ions in the solution is 180 g / l. The waste solution is again drained into the bone and treated with a calculated amount of sodium sulfide. The solution is filtered and adjusted with hydrochloric acid in a manner similar to the first regeneration. After the second regeneration, the etching is again carried out until a copper ion content of 180 g / l is obtained. The operations of deposition of copper in the form of sulfide, filtration and adjustment of the solution with hydrochloric acid are carried out similarly to the first and second regeneration plants. After the third chemical regeneration, the solution is recycled and the etching is carried out until the pickling rate drops sharply. The study was carried out with peroxide-copper-chloride pickling solution. Sodium sulfide crystallohydrate was used as a reagent. The composition of the etching solution for the regenerated copper contains g / l: copper chloride (in terms of metal) 180 hydrochloric acid | (35% concentration), HC1 100 hydrogen peroxide, H Oj33 sodium chloride 100 During the etching process, periodically control the copper content in the solution, take samples and analyze them by an analytical method. For the experiment, spent pickle is used with a total copper content, for example, 180 g / l. Under normal conditions, copper is precipitated until a copper concentration of 120 g / l is reached. The copper sulfide precipitate is separated by filtration. Then, the filtrate is corrected with hydrochloric acid, based on chemical analysis data, and defended within 24 hours. The copper-specific solution is returned to the process cycle and copper is poisoned in it. This solution has an improved etching quality and the etching rate in it increases. The subsequent deposition of copper is carried out similarly to the previous one. When the concentration of copper in the solution is close to the optimal 90-120 g / l, the etching rate is greatest in the range of 0.0376-0.0575 g. Moreover, the etching rate in the updated copper deposition solution is greater than in the spent concentration within the optimum concentration. After three times precipitation, the etching rate drops sharply. To precipitate the required amount of copper, a preliminary calculation is carried out, based on the reaction equation: CuCl Na2S CuS4- + 2 NaCE. The calculation of the required amount of sodium sulfide, taking into account the water of crystallization required for the deposition of 60 g / l of copper in our example:,, G MgK1, 0, .-. Na, S-9H where M | 78 molecular weight NajS; M, 135 molecular weight CuCE; K is the amount of chlorine copper CuC 2,., M where Cuj, g / l is the amount of copper ions required to precipitate 64 is the atomic mass of copper 240 is the molecular weight of crystalline hydrate 9 HjO. In our example, Cu is 60 g / l, therefore - Na, S-9H O 225 g / l 2 LF In the process of precipitating copper sulfide, sodium sulfide partially interacts with hydrochloric acid, therefore it is necessary to take sodium sulfide in 1.2-1 , 3 times more compared with stoheometry. The etching rate in both the spent and regenerated solution is determined by changing the weight of the copper sample for 10 min at 40 ° C and vigorous stirring. Sample weight is 1 g. The accumulation of sodium chloride up to 100-110 g / l and sulphate of ions up to 25 g / l does not affect the etching rate of copper. The results of the experiments after three times the deposition of the spent pickling solution are shown in the table. To justify the limits, we present the results of experiments. The first addition of sodium sulfide reagent is introduced at a copper concentration in the solution of 120 g / l, and the amount of the reagent is added, based on the calculation, maintaining the copper content in the solution from 90 to 120 g / l. Using sodium sulfide, it can regenerate the waste solution three times. The etching rate after the third regeneration is laid in the speed fork. Moreover, the etching rate in the solution after regeneration with a copper content of 90-120 g / l corresponds to 0.0376-0.0575 g, while the etching rate in the spent solution with a copper content of 90-120 g / l is 0.0278-0 , 0353 g. Thus, after chemical regeneration, an increase in the rate of etching is achieved. In a known method, a solution for etching copper, containing hydrochloric acid, hydrogen peroxide and chlorine copper, is adjusted by metered delivery of hydrochloric acid and hydrogen peroxide with the accumulation of monovalent copper ions greater than 1-1.5 g / l, as with the accumulation of monovalent copper more than 1.5 g / l, the etching rate decreases sharply. The disadvantage of this method is that with the accumulation of divalent copper Cu up to 180 g / l 5/6 of the spent solution is discharged into wastewater. In comparison with the known method of the present invention, an increase in the etching rate in the regenerated solution is achieved. In the known method, after the treatment of the solution, the efficiency of the etching process is reduced due to the impurities formed, and in the proposed method the impurities do not affect the etching process, since the low solubility of copper sulfide, therefore contaminations that are almost unavoidable during etching, in our case, affect less than when using the effect of changing the solubility of copper sulfate. In addition, when treated with sodium sulfide, impurities in the solution, tin, lead, and other metals are precipitated along with copper, which, further purifying the solution, increases the utilization rate of the solution up to three times. The implementation of the proposed method of regeneration of the spent pickling solution allows the solution to be returned three times and, moreover, in the regenerated solution, the etching takes place at a faster rate than in the solution before processing. DETAILED DESCRIPTION OF THE INVENTION A method for treating spent copper pickling solution based on hydrochloric acid, hydrogen peroxide and copper chloride, including adjustment of the solution, is due to the fact that, in order to improve performance, sodium sulfide is introduced into the solution before adjustment. providing the content of copper ions in a solution of 90-120 g / l.